FISHERY INDUSTRIES OF THE UNITED STATES, 1930 121 



As stated in the 1929 report of this division, this bureau arranged 

 with the Bureau of Chemistry and Soils a cooperative research pro- 

 gram to study the nutritive value of marine products and assigned a 

 chemist for this purpose to the laboratories of the protein and nutri- 

 tion division of the Bureau of Chemistry and Soils, United States 

 Department of Agriculture. As previously reported, the first studies 

 dealt with the vitamins A and D content of such commercial fish 

 oils produced in the United States and Alaska as tuna, salmon, 

 pilchard (California sardine), Alaska herring, Maine herring, and 

 menhaden. Some of these oils were found to be good sources of 

 vitamin D for animal feeding. It was thought that heat and oxida- 

 tion in the process of manufacture now in commercial use might 

 adversely afi'ect the vitamin content of these oils. Accordingly, 

 studies of the effect of different processes of manufacture of experi- 

 mentally prepared oils were inaugurated. Some of these have been 

 completed. A study of the above character made in connection with 

 menhaden fish oils revealed that, whereas commercial menhaden oil 

 contained only about three-fourths the vitamin D content of medicinal 

 cod-liver oil, menhaden oils prepared according to some of the experi- 

 mental processes described in the by-products section of this report 

 were equally as potent in vitamin D as medicinal cod-liver oil. 



Salmon oils extracted from the canned offal of the five commercial 

 species of salmon were tested. Four out of the five tested species 

 proved to be equal to medicinal cod-liver oil in content of vitamin A. 

 All of these oils were equal to medicinal cod-liver oil in vitamin D, 

 and three of the species were twice as potent in vitamin D as medicinal 

 cod-liver oil. Oils extracted from the edible canned product of the 

 five species of salmon proved to be equal in vitamin D content to 

 medicinal cod-liver oil; however, the vitamin A content was rela- 

 tively low. This may be due to the canning process or present 

 cannery methods. Other experiments being conducted by our bio- 

 chemists in the laboratories of the Bureau of Chemistry and Soils 

 are (a) the vitamins A and D content of burbot liver oil, (6) the chem- 

 ical and physical characteristics of burbot liver oil, (c) the vitamin D 

 content of oysters from different localities of the United States. 



In view of the fact that American fish oils are comparatively rich 

 in vitamins A and D, these may replace imported cod-liver oil in 

 this country and lessen our dependence on foreign sources of supply. 

 Experiments indicating the relatively high vitamin content of canned 

 salmon should be of considerable interest to our great salmon-canning 

 industry. 



The bureau's investigator at Johns Hopkins University has com- 

 pleted certain experimental work in connection with the mineral 

 content of fish meals and kelp meal. Spectographic analyses of the 

 mineral elements occurring in these products were made. In some 

 instances some of the less common elements were identified in quanti- 

 ties too small to be detected by ordinary chemical analyses. As far 

 as possible, however, chemical analyses were conducted to verify 

 the spectographic determinations. The following mineral constitu- 

 ents were found, either by chemical or spectographic analyses: 

 Aluminum, barium, boron, calcium, chromium, copper, fluorine, iron, 

 iodine, lead, lithium, magnesium, manganese, nickel, niobium, 

 phosphorus, potassium, sulphur, silicon, silver, sodium, strontium, 

 thallium, tin, titanium, vanadium, and zinc. 



